The present invention relates to a retrofit manifold, system and process for converting a solvent vapor degreaser to an aqueous solution degreaser for the removal of contaminants from workpieces, manufactured articles and other parts.
A wide variety of methods and devices are known for degreasing or otherwise removing contaminants from the surfaces of parts. One common technique is to use a vapor degreaser which consists of a tank filled with a liquid solvent. The contaminated pieces, articles or parts are suspended over the solution in a basket so that the vapors from the liquid solvent solution dissolve the contaminants and cause the contaminants to separate from the articles and drip down into the solvent below.
Most often the contaminant has an oil base which causes the contaminants to mix with the solvent once it is removed from the parts. A major problem associated with vapor degreasers is that the solvent is highly volatile, noxious and not readily degradable in the environment. Also, such solvents include fluorinated and chlorinated hydrocarbons which have also been found to deplete the ozone layer in the upper atmosphere. In addition, cleaning solvents often are flammable, toxic and constitute "hazardous waste" which require specialized handling when they must be discarded.
Due to the hazards of using vapor degreasers and their solvents and the danger to the environment, aqueous solution degreasers have been developed as a solution to the problem. The aqueous or water based solutions that are used for the aqueous solution degreasers for removing contaminants from parts or articles alleviate the many problems that were associated with the vapor degreasers. The aqueous degreasers come in several varieties such as those that consist of a tank in which a basket of parts or articles is suspended and solution is sprayed from manifolds or pipes through nozzle attachments. By spraying the aqueous solution the contaminants are removed from the parts and are later drained or skimmed from the tank. Other types of aqueous degreasers consist of directly submerging the parts or articles in the solution itself. The aqueous solution is then allowed to react and remove the contaminants and is later removed from the tank.
U.S. Pat. No. 4,651,762 to Bowden and U.S. Pat. No. 4,082,867 to Henley, et al. both disclose the use of water based or aqueous, emulsion forming cleaning solutions for removing oil from manufactured articles. Both patents advocate the use of agitation and separate the oil from the cleaner to allow reuse of the cleaner. After cleaning the articles, oil is removed from the aqueous solution using a skimming technique, taking advantage of the fact that the lighter oil floats to the surface.
U.S. Pat. No. 4,844,743 to Koblenzer, et al. discloses a method and system for cleaning work pieces with a liquid solvent put in a treatment chamber or tank in which the work pieces are submerged. A series of manifolds are employed so that the nozzles on the manifold spray liquid solvent from both a top and bottom direction within the tank.
U.S. Pat. No. 3,888,693 to Schevey, et al. discloses a multi-phase rinse and recovery method using an apparatus that removes and recovers contaminated liquid from unclean articles once they are submerged within a tank. A series of nozzles are employed so that the liquid is sprayed in three directions. The liquid is sprayed at the contaminated articles from left to right, right to left and bottom to top.
U.S. Pat. No. 5,051,135 to Tanaka, et al. discloses a cleaning method using a solvent while preventing the discharge of the solvent vapors to the environment. A tank is utilized having a manifold with nozzles located at the top of the tank. The nozzles at the top of the tank spray liquid solvent from the top of the tank to the bottom of the tank thereby cleaning contaminated articles.
Although there has been a shift in the use of degreasing apparatus from the older style vapor degreasers to the use of aqueous solution degreasers, a fully satisfactory, economical and efficient method and system still has not been developed for converting the older style solvent vapor degreasers to the environmentally safe aqueous solution degreasers.